铁系材料去除水体中四环素的性能研究
发布时间:2018-02-27 12:52
本文关键词: 铁 四环素 絮凝 络合物 出处:《湖南农业大学》2015年硕士论文 论文类型:学位论文
【摘要】:四环素在畜禽养殖业中广泛使用,其排放对水体环境产生严重的危害。本论文利用淀粉包覆的零价纳米铁(starch-NZVI)去除水体中的四环素(TC),研究了四环素初始浓度、pH,不同反应时间,离子的类型,离子强度等因素对去除效果的影响。当四环素原始浓度为500 mg/L,零价纳米铁0.20 g/L的时候,去除四环素的效率高达99%,其中吸附和降解占30%,絮凝作用占69%。零价纳米铁去除四环素容量随着四环素的浓度升高而升高,当四环素原始浓度为1000 mg/L,最大去除容量4137.3 mg/g。此外,从絮凝作用的来看,它受到pH和离子强度的影响非常大。中性条件和高盐离子浓度可以提高去除效率和絮凝沉降速率。99%Fe-TC的络合物一般在7天完成絮凝,在2M NaCl条件下,仅需要24小时。XPS分析显示絮凝物中Fe由88%Fe(Ⅲ)和12%Fe(Ⅱ)组成。LC-MS显示有机成分包括TC和它经过氧化后的降解产物。我们的结果是首次报道零价纳米铁通过降解和絮凝的复合作用高效去除水中的四环素。为了快速去除水体中的四环素,我们发现Fe(Ⅲ)与四环素易形成带正电荷的络合物质,它能快速高效地被聚丙烯酸-丙烯酰胺复合树脂吸附去除。通过研究材料中O=C-NH-C的数量、铁离子与四环素含量比、盐离子浓度对去除四环素效果的影响,结合最优化条件下的吸附热力学、吸附动力学发现Fe(Ⅲ)能够显著促进四环素被树脂吸附,Fe(Ⅲ)的去除几乎不受四环素影响。在500 min内,大量四环素被去除。初步探讨出机理如下:Fe(Ⅲ)和TC先形成Fe-TC络合物,然后被树脂吸附,其中铁离子具有桥梁作用,其具有大量空轨道,不仅与四环素有配位作用,而且与树脂中的CONH2\ O=C-NH-C有配位作用,所以随着树脂中O=C-NH-C越多,去除四环素的效果越高。Fe(Ⅲ)、Fe-TC络合物与羧基的反应可能是离子交换作用,但是羧酸基因与铁离子的相互作用力强,,会破坏Fe-TC络合物结构,而形成COO-Fc(Ⅲ)的结构。
[Abstract]:Tetracycline is widely used in livestock and poultry breeding, and its discharge has serious harm to the water environment. In this paper, the initial concentration of tetracycline (pH) and different reaction time were studied by using starch-NZVI (starch coated nano-iron) to remove tetracycline (TCN) from water. When the original concentration of tetracycline is 500 mg / L, and the zero valence nanocrystalline iron is 0.20 g / L, The efficiency of removing tetracycline is as high as 99mg / L, of which 30 are adsorbed and degraded, and 69 are flocculated. The removal capacity of tetracycline increases with the increase of tetracycline concentration, when the original concentration of tetracycline is 1000 mg / L, the maximum removal capacity of tetracycline is 4137.3 mg / g. From the point of view of flocculation, it is greatly affected by pH and ionic strength. Neutral conditions and high salt ion concentration can improve the removal efficiency and flocculation rate. The flocculation of 99-TC complex is generally completed in 7 days, and under the condition of 2m NaCl. It only takes 24 hours. XPS analysis shows that Fe in the flocculation consists of 88 (鈪
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